User registration on Cuddlers CMS

User registration on the Cuddlers CMS after user has followed the states:registration:* leg of the customer journey.
Because of the way jsbox works, the app is run every time a message is sent in. If a tester run happens without any `.input`s or `.start`s, I think we do a session start by default. This means that this test will pass, but that we reached this state in a different way than a user would. This kind of check is usually best done in the test where the user reached the state, so for this case, over [here](https://github.com/praekelt/vumi-go-cuddlers/blob/feature/issue-1-user-registration-on-cuddlers-cms/test/app.test.js#L555).